Why does documentation states that R09912 purge program for F0902 should only be purged for prior ye

We have a need to purge F0902 data for one of our work in progress budget ledgers, and we want to use R09912 regularly just for that data selection on Bx ledger for future years.  However documentation I found specifies that we should make sure that the JDE company should be in the current year to purge prior year, but made no mention of future year purge.